The nation’s largest police union, which enthusiastically endorsed Donald Trump for president back in September, is now expressing concern over the Trump administration’s threat to cut federal funding for public safety programs to punish so-called sanctuary cities that refuse to cooperate with federal immigration officials.

On Monday, Attorney General Jeff Sessions announced that the Trump administration will make good on its threat to cut Justice Department grants from the roughly 600 cities and counties across the country that limit information-sharing with Immigration and Customs Enforcement. Many of the nation’s biggest cities have declared themselves sanctuaries for immigrants, including New York City, Los Angeles, San Francisco, Boston, Chicago, and Washington D.C.

The DOJ grants, which total about $4 billion every year, support local programs to tackle human trafficking, sexual assault, gang violence, mental health, gun crimes and other safety issues.

According to Reuters, FOP executive director Jim Pasco said his union is “concerned that cuts in funding could hurt police departments in those areas.”

Pasco, who did not immediately respond to TPM’s request for an interview, said the union “would oppose any move to restrict federal funding for police.”

The Federal Order of Police does not support sanctuary policies – though many chiefs of police across the country do, arguing that they can better do their jobs if all residents feel comfortable coming forward and talking to them without fear of deportation. The FOP, however, urged Trump in December to take a number of actions to ramp up immigration enforcement on the local level, roll back restrictions on racial profiling, and gut protections for undocumented people who were brought to the country as children.